Gain-control methods of transmitter modulators

ABSTRACT

An apparatus comprising a plurality of switchable full step mixer unit cells, wherein each switchable full step unit cell is configured to, when the full step transceiver mixer unit cell is turned on, increase the gain experienced by an electronic signal by a full step increment, and wherein the step increment is substantially constant regardless of temperature; and at least one switchable partial step mixer unit cell configured to, when the partial step transceiver mixer unit is turned on, increase the gain experienced by the electronic signal by a predetermined step increment less than that of a full step, and wherein the partial step increment is substantially constant regardless of temperature.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of, and claims priority under 35U.S.C. §120 to, application Ser. No. 11/947,240, filed on Nov. 29, 2007,now issued as U.S. Pat. No. ______, entitled “GAIN-CONTROL METHODS OFTRANSMITTER MODULATORS”. The subject matter of these earlier filedapplications are hereby incorporated by reference.

TECHNICAL FIELD

This description generally relates to the control of the gain of anelectrical signal, and more specifically to the control of the gain of acommunication signal utilizing a transformer.

BACKGROUND

Wideband Code Division Multiple Access (WCDMA), in this context, isoften a type of third generation (3G) cellular network. Moretechnically, WCDMA is often a wideband spread-spectrum mobile airinterface or protocol that utilizes the direct sequence Code DivisionMultiple Access (CDMA) signaling method to achieve higher speeds andsupport more users compared to the implementation of time divisionmultiplexing (TDMA) used by second generation (2G) networks. It isunderstood that WCDMA is merely one non-limiting communication techniqueto which the disclosed subject matter may be applied.

Often a WCDMA device will include a form of gain control. This maygenerally allow a user to control the strength of a signal transmittedby the WCDMA device. In a typical WCDMA transmitter some portion of thegain-control is built into a pre-amplification driver and the rest ofthe gain control is frequently distributed amongst a transceiver mixerand base-band filter. The gain control is frequently divided intodiscrete chunks, called “gain steps”.

SUMMARY

A system and/or method for communicating information, substantially asshown in and/or described in connection with at least one of thefigures, as set forth more completely in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a system for controlling the gain of anelectrical signal in accordance with the disclosed subject matter.

FIG. 2 is a block diagram of a system for controlling the gain of anelectrical signal in accordance with the disclosed subject matter.

FIG. 3 is a schematic diagram of a system for controlling the gain of anelectrical signal in accordance with the disclosed subject matter.

FIG. 4 is a schematic diagram of a system for controlling the gain of anelectrical signal in accordance with the disclosed subject matter.

FIG. 5 is a flowchart of a technique for controlling the gain of anelectrical signal in accordance with the disclosed subject matter.

DETAILED DESCRIPTION

FIG. 1 is a block diagram of a system 100 in accordance with thedisclosed subject matter for controlling the gain of an electricalsignal. In one embodiment, the system 100 may include a transmitter 102,an amplifier 107 and an antenna 105. In one embodiment, the transmitter102 may be configured to receive an input signal and produce an outputsignal. In one embodiment, the transmitter 102 may be included as partof or be an integrated circuit or a microchip. In one embodiment, theinput signal may include an in-phase portion (In-phase input signal104-I) and a quadrature phase portion (Quadrature-phase input signal104-Q). In one embodiment, the amplifier 107 may be configured toproduce an amplification of the output signal. In one embodiment, theantenna 105 may be configured to facilitate a transmission of theamplified output signal.

In one embodiment, the transmitter 102 may include a digital-to-analogconverter (DAC) 106, a baseband filter (BBF) 108, a mixer unit 110, anda transformer 114. In one embodiment, the DAC 106 may be configured toconvert a digital signal into an analog signal. In one embodiment, theDAC 106 may include an in-phase portion (DAC, In-phase 106-I) and aquadrature phase portion (DAC, Quadrature 106-Q) configured to receivethe In-phase input signal 104-I and Quadrature-phase input signal 104-Q,respectively.

In one embodiment, the baseband filter (BBF) 108 may be configured toproduce a baseband signal by filtering an input signal. In oneembodiment, the baseband filter (BBF) 108 may be configured to produce,at least, four baseband signals utilizing an input signal. In oneembodiment, the four baseband signals may include the following portionsor phases: a positive in-phase, a negative in-phase, a positivequadrature phase, and a negative quadrature phase. In one embodiment,the BBF 108 may include an in-phase portion (BBF, In-phase 108-I) and aquadrature phase portion (BBF, Quadrature 108-Q) configured to receivethe in-phase output of DAC 106-I or the quadrature output of the DAC106-Q, respectively. In various embodiments without a DAC 106, the BBF108 may receive the input signal (and any in-phase and quadraturecomponents of the input signal) directly.

In one embodiment, the mixer unit 110 may be configured to produce anintermediate signal which is a sum of multiplications of portions of thebaseband signal and portions of a local oscillator signal. In oneembodiment, the local oscillator signal may include an in-phase portion(In-phase local oscillator signal 112-I) and a quadrature phase portion(Quadrature-phase local oscillator signal 112-Q). In one embodiment, themixer unit 110 may include an in-phase multiplier 110-I configured tomultiply an in-phase portion of the baseband signal and an in-phaselocal oscillator signal 112-I. In one embodiment, the mixer unit 110 mayinclude a quadrature-phase multiplier 110-Q configured to multiply aquadrature-phase portion of the baseband signal and a quadrature-phaselocal oscillator signal 112-Q. It is understood that, in variousembodiments, the multipliers may include more complex structures andthat the illustrated multipliers are merely one illustrativenon-limiting embodiment of the disclosed subject matter. In oneembodiment, the mixer unit 110 may include a summer 111 configured tosum the results of the multipliers 110-I & 110-Q.

In one embodiment, the mixer unit 110 may include a number of switchablemixer unit cells configured to increase the gain experienced by anelectronic signal by step increments, and wherein the step incrementsare substantially constant regardless of temperature inside theRadio-Frequency Integrated Circuit (RF-IC). In one embodiment, theswitchable mixer unit cells may be switched on and off in order toincrease or decrease the gain experienced by a signal. In oneembodiment, the mixer unit 110 may include a number of switchable mixerunit cells some of which are configured to provide a full gain step,others of which may be configured to provide a partial gain step.Examples of such embodiments are described in more detail below inrelation to FIGS. 2, 3, 4, and 5.

In one embodiment, each gain step, both full and partial, may besubstantially constant regardless of temperature. For example, if eachgain step equals 6 dB, to pick a non-limiting illustrative gain stepvalue, the gain step may be substantially constant regardless of thetemperature of the mixer unit 110. In a specific example, a user inHelsinki may be indoors where the temperature is 27 C and experience again step of 6 dB. If that user goes outside where the temperature is −3C, a gain step of substantially 6 dB should, in one embodiment, beexperienced. It is understood that is merely one specific non-limitingillustrative example and that the disclosed subject matter is notlimited to any particular location, temperature or gain step value.

In one embodiment, the transmitter 102 may include a transformer 114. Inone embodiment, the transformer 114 may be configured to receive theoutput signal of the mixer unit cells, and transmit the output signal toan amplifier 107. In one embodiment, the intermediate signal may beprovided by the mixer unit 110 and may include a number of portions. Inone embodiment, the selection of the gain provided by the transformer114 may be selected and changed dynamically.

FIG. 2 is a block diagram of a system 200 for controlling the gain of anelectrical signal in accordance with the disclosed subject matter. Inone embodiment, the system may be or include a mixer unit 200 such asmixer unit 110 of FIG. 1. In one embodiment, the mixer unit 200 mayinclude a number of switchable mixer unit cells configured to increaseor decrease the gain experienced by an electronic signal by stepincrements, and wherein the step increments are substantially constantregardless of temperature. In one embodiment, the mixer unit may includea number of switchable mixer unit cells 208, 208 n, & 210 some of whichare configured to provide a full gain step (e.g., 208 & 208 n), othersof which may be configured to provide a partial gain step (e.g., 210).

In one embodiment, the mixer unit cells 208, 208 n & 210 may receive alocal oscillator signal 202 and a baseband signal 204. In oneembodiment, the local oscillator signal 202 may include both positiveand negative portions and in-phase and quadrature phase portions. In oneembodiment, the local oscillator signal 202 may include a positivein-phase local oscillator signal 202 a, a negative in-phase localoscillator signal 202 b, a positive quadrature phase local oscillatorsignal 202 c, and a negative quadrature phase local oscillator signal202 d. In one embodiment, the baseband signal 204 may include bothpositive and negative portions and in-phase and quadrature phaseportions. In one embodiment, the baseband signal 204 may include apositive in-phase baseband signal 204 a, a negative in-phase basebandsignal 204 b, a positive quadrature phase baseband signal 204 c, and anegative quadrature phase baseband signal 204 d.

In one embodiment, the mixer unit cells 208, 208 n & 210 may combine thelocal oscillator signal 202 and a baseband signal 204 to produce anoutput signal 206. In one embodiment, the output signal 206 may includea positive output signal 206 a and a negative output signal 206 b. Inone embodiment, the combination may include the multiplication of the,or portions of the, local oscillator signal 202 and a baseband signal204 in the time domain. In one embodiment, the output of, or portions ofthe outputs of, each of the mixer unit cells 208, 208 n & 210 may becombined to form the output signal 206, or portions of the output signal206. In one embodiment, the combination of the outputs may include theaddition of the outputs.

In one embodiment, the switchable full step mixer unit cells 208 & 208 nmay be configured such that when the switchable full step mixer unitcell is turned on, the gain experienced by an electronic signal isincreased by a full step increment. In one illustrative example, a fullgain step may be 6 dB; therefore, if a signal is already experiencing 6dB of gain turning on or activating a switchable full step mixer unitcell 208 may increase the gain to 12 dB. FIG. 2 shows switchable fullstep mixer unit cells 208 & 208 n, implying that, in one embodiment, themixer unit 200 may include a plurality of switchable full step mixerunit cells (e.g., 208 and 208 a through 208 n in FIG. 2). In oneembodiment, the mixer unit 200 may include 2¹⁰ (or 1,024) switchablefull step mixer unit cells 208. In one embodiment, the mixer unit 200may be allocated to provide a gain range of at least 60 dB. However, itis understood that the illustrative values are merely examples, and thatthe disclosed subject matter is not limited to this example.

In one embodiment, the switchable partial step mixer unit cells 210 maybe configured such that when the switchable partial step mixer unit cell210 is turned on, the gain experienced by an electronic signal isincreased by a predetermined step increment less than that of a fullstep increment. In one illustrative example, a full gain step may be 6dB and a partial gain step may be 2 dB; therefore, if a signal isalready experiencing 6 dB of gain turning on or activating a switchablepartial step mixer unit cell 210 may increase the gain to about 10.26dB. In one embodiment, the mixer unit 200 may include a plurality ofswitchable partial step mixer unit cells 210. In one embodiment, thepredetermined partial gain step provided by each partial step mixer unitcells 210 may be values, such as, for example, a half-full step (−6 dB),a quarter-full step (−12 dB), or an eighth-full step (−18 dB). However,it is understood that the illustrative values are merely examples, andthat the disclosed subject matter is not limited to this example.

In one embodiment, a number of partial gain steps may substantiallyequal a full gain step. In such an embodiment, the mixer unit 200 may beconfigured to, as gain is increased, turn on or activate a number ofswitchable partial step mixer unit cells 210 until a full gain step isreached. In one embodiment, the triggering point may be the when oneadditional partial step would equal a full gain step and the mixer unit200 receives an instruction to increase the gain by another partial gainstep. At that point, in one embodiment, the mixer unit 200 may turn offthe number of switchable partial step mixer unit cells 210 and turn on aswitchable full step mixer unit cell 208 or 208 n. Conversely, in oneembodiment, the opposite may occur as the gain experienced by a signalis decreased. In one embodiment, this may allow greater granularity whencontrolling a gain to a signal.

In one embodiment, the pre-amplification driver (discussed above in the“Background” section) may be removed from a transmitter, for exampletransmitter 102 of FIG. 1. In one embodiment, the gain normallyallocated to the pre-amplification driver may be distributed amongst themixer unit 110 or 200 and the base-band filter 108.

In one embodiment, this may be accomplished by increasing the number ofswitchable full step mixer unit cells 208 & 208 n. In one embodiment, ifthe gain range allocated to the now removed pre-amplification driver was12 dB, the gain range allocated to the mixer unit 200 may be increasedfrom 60 db to 72 dB. In embodiments where the full gain step issubstantially equal to 6 dB, a 60 dB mixer unit 200 may include 2¹⁰ (or1,024) switchable full step mixer unit cells 208. However, a 72 dB mixerunit 200 may include 2¹² (or 4,096) switchable full step mixer unitcells 208. However, it is understood that these illustrative values aremerely examples, and that the disclosed subject matter is not limited tothis example.

In one embodiment, the allocation of gain range may be accomplished byincreasing the full gain step value, as compared to embodimentsincluding a pre-amplification driver. In one embodiment, the gaincontrol granularity of the pre-amplification driver embodiment may bepreserved or increased with the addition of at least one switchablepartial step mixer unit cell. In one embodiment, if the gain rangeallocated to the now removed pre-amplification driver was 12 dB, thegain range allocated to the mixer unit 200 may be increased from 60 dbto 72 dB. In embodiments where the mixer unit 200 may include 2¹° (or1,024) switchable full step mixer unit cells 208, the full gain stepvalue may be increased from 6 dB to 7.2 dB thereby allowing a full gainrange of 72 dB without the increase in the number of switchable fullstep mixer unit cells 208. In one embodiment, the mixer unit 200 mayinclude a number of switchable partial step mixer unit cells 210.

In one embodiment, the each partial step may be substantially equal to afraction of a full gain step, such that the sum of the available partialgain steps (plus one additional partial step, in some embodiments) maybe substantially equal to a full gain step. In another embodiment, thepartial gain step may be substantially equal to 6 dB. In such anembodiment, the mixer unit 200 may include combinations of switchablepartial step mixer unit cells and switchable full step mixer unit cells208 in non-integer ratio arrangements. In such an embodiment, the mixerunit 200 may include 2¹⁰ (or 1,024) switchable full step mixer unitcells 208 and four switchable partial step mixer unit cells 210: ahalf-full step (−6 dB), a quarter-full step (−12 dB), an eighth-fullstep (−18 dB) and a sixteenth-full step (−24 dB). In this embodiment,the mixer unit 200 may include a total of 1,028 mixer unit cells asopposed to the 4,096 mixer unit cells of the previously discussedembodiment. In one embodiment, the total number of mixer unit cells mayequal that of the pre-amplification driver embodiment (e.g., 2¹⁰ or1,024) but be allocated amongst switchable full step mixer unit cells208 and switchable partial mixer unit cells 210. However, it isunderstood that the illustrative values are merely examples, and thatthe disclosed subject matter is not limited to this example.

In one embodiment, the amount of gain requested may be applied in anon-contiguous fashion. In such an embodiment, a number of switchablefull gain step mixer unit cells and a number of switchable partial gainstep mixer unit cells may be activated substantially simultaneously,allowing the intermediate gain values to be skipped. In one embodiment,the gain provided by each gain step, full and partial may be negativesuch that the signal is attenuated. In one embodiment, the mixer unit110 may also turn off or deactivate the switchable mixer unit cells,both full and partial step as appropriate. In one embodiment, a user maybe capable of both increasing and decreasing the gain applied orexperienced by a signal.

FIG. 3 is a schematic diagram of a system for controlling the gain of anelectrical signal in accordance with the disclosed subject matter. Inone embodiment, each switchable full step mixer unit cell 208 of FIG. 2may include a mixer circuit. In one embodiment, each mixer circuit ofthe switchable full step mixer unit cell 208 of FIG. 2 may include anin-phase portion and a quadrature phase portion (not shown); and whereineach portion of the mixer circuit includes a positive sub-portion and anegative sub-portion. FIG. 3 illustrates the in-phase portion of aswitchable full step mixer unit cell 300. In one embodiment, thein-phase portion 300 of a switchable full step mixer unit cell 208 mayinclude an in-phase positive sub-portion 308 a and a negative in-phasesub-portion 308 b. In one embodiment, the quadrature-phase portion (notshown) of a switchable full step mixer unit cell 208 may be analogous tothe in-phase portion 300 with the exception that the quadrature-phaseportion may receive quadrature-phase signals, whereas the in-phaseportion 300 may receive in-phase signals.

In one embodiment, the in-phase positive sub portion 308 a may include alocal oscillator switching circuit 304 and a cascode circuit 306. In oneembodiment, each sub portion 308 may include a first part 305 having alocal oscillator switching circuit 304 and a top of a cascode circuit306 and a second part 307 having a bottom of a cascode circuit 306. Itis understood that these groupings while shown on different sub-portions308 a & 308 b of FIG. 3 occur in both sub-portions 308 a & 308 b and aremerely separated so as to not obscure the drawing. It is also understoodthat the terms “top” and “bottom” are relative terms used todifferentiate the elements of the cascode circuit 306 and in no waylimit or dictate the physical orientation of the disclosed subjectmatter.

In one embodiment, the local oscillator switching circuit 304 may beconfigured to receive a local oscillator input signal 202. In oneembodiment, the In-phase positive sub-portion 308 a may receive positivein-phase local oscillator input signal 202 a; whereas, the In-phasenegative sub-portion 308 b may receive negative in-phase localoscillator input signal 202 b. And so on, for the quadrature-phaseportion.

In one embodiment, the local oscillator switching circuit 304 mayinclude a positive transistor 310 a and a negative transistor 312 a. Inone embodiment, the gates of both the positive transistor 310 a andnegative transistor 312 a may receive or be coupled with the positivein-phase local oscillator input signal 202 a. In one embodiment, thesources of both the positive transistor 310 a and negative transistor312 a may be coupled with each other and the cascode circuit 306. In oneembodiment, the drain of the positive transistor 310 a may provide apositive output signal 206 a, and the drain of the negative transistor312 a providing a negative output signal 206 a. It is understood thatthe configuration of the negative in-phase sub-portion 308 b and thequadrature-phase portion may be analogous to the positive in-phasesub-portion 308 a, described above.

In one embodiment, the cascode circuit 306 may include a top part and abottom part. Although once again, it is understood that the terms “top”and “bottom” are relative terms used to differentiate the elements ofthe cascode circuit 306 and in no way limit or dictate the physicalorientation of the disclosed subject matter. In one embodiment, the topof the cascode circuit 306 may include a biasing transistor 314 aconfigured to receive a biasing input signal 302. In one embodiment, thegate of the biasing transistor 314 a may be coupled with the biasinginput signal 302. In one embodiment, drain of the biasing transistor 314a may be coupled with the local oscillator switching circuit 304. In oneembodiment, the source of the biasing transistor 314 a may be coupledwith the bottom of the cascode circuit 306. It is understood that theconfiguration of the negative in-phase sub-portion 308 b and thequadrature-phase portion may be analogous to the positive in-phasesub-portion 308 a, described above.

In one embodiment, bottom of the cascode circuit 306 may be configuredto receive a baseband input signal 204. In one embodiment, the secondpart 307 of each sub-portion of the switchable full step mixer unit cell208 may include the bottom of the cascode circuit 306. In oneembodiment, the bottom of the cascode circuit 306 may include a fullstep baseband transistor 316 a. In one embodiment, the gate of the fullstep baseband transistor 316 a may receive or be coupled with thepositive in-phase baseband signal 204 a. In one embodiment, the drain ofthe full step baseband transistor 316 a may be coupled with the top ofthe cascode circuit 306. In one embodiment, the source of the full stepbaseband transistor 316 a may be thought to be coupled with a ground. Inone embodiment, the ground may be effective, relative, or absolute.

In one embodiment, the full step baseband transistor 316 a may include awidth, W. In one embodiment, the width of the full step basebandtransistor 316 a may affect the gain provided by the positive in-phasesub-portion 308 a and may affect the amount of current allowed to flowthrough the full step baseband transistor 316 a. In one embodiment, thewidth, W, of the full step baseband transistor 316 a may affect thevoltage at the interface between the top and bottom of the cascodecircuit 306.

FIG. 4 is a schematic diagram of a system for controlling the gain of anelectrical signal in accordance with the disclosed subject matter. Asdiscussed above, in one embodiment, each switchable partial step mixerunit cell 210 of FIG. 2 may include a mixer circuit. In one embodiment,each mixer circuit of the switchable partial step mixer unit cell 210 ofFIG. 2 may include an in-phase portion and a quadrature phase portion(not shown); and wherein each portion of the mixer circuit includes apositive sub-portion and a negative sub-portion. FIG. 4 illustrates thein-phase portion of a switchable partial step mixer unit cell 400. Inone embodiment, the in-phase portion 400 of a switchable partial stepmixer unit cell 210 may include an in-phase positive sub-portion 408 aand a negative in-phase sub-portion 408 b. In one embodiment, thequadrature-phase portion (not shown) of a switchable partial step mixerunit cell 210 may be analogous to the in-phase portion 400 with theexception that the quadrature-phase portion may receive quadrature-phasesignals, whereas the in-phase portion 400 may receive in-phase signals.

In one embodiment, the in-phase positive sub portion 408 a may include alocal oscillator switching circuit 304 and a cascode circuit 406. In oneembodiment, each sub portion 408 may include a first part 305 having alocal oscillator switching circuit 304 and a top of a cascode circuit406 and a second part 407 having a bottom of a cascode circuit 406. Itis understood that these groupings while shown on different sub-portions408 a & 408 b of FIG. 4 occur in both sub-portions 408 a & 408 b and aremerely separated so as to not obscure the drawing. It is also understoodthat the terms “top” and “bottom” are relative terms used todifferentiate the elements of the cascode circuit 406 and in no waylimit or dictate the physical orientation of the disclosed subjectmatter.

In one embodiment, the local oscillator switching circuit 304 may beconfigured to receive a local oscillator input signal 202. In oneembodiment, the In-phase positive sub-portion 408 a may receive positivein-phase local oscillator input signal 202 a; whereas, the In-phasenegative sub-portion 408 b may receive negative in-phase localoscillator input signal 202 b. And so on, for the quadrature-phaseportion. In one embodiment, the local oscillator switching circuit 304of the switchable partial step mixer unit cell 210 may be substantiallyequivalent to the local oscillator switching circuit 304 of theswitchable full step mixer unit cell 208.

In one embodiment, the local oscillator switching circuit 304 mayinclude a positive transistor 310 a and a negative transistor 312 a. Inone embodiment, the gates of both the positive transistor 310 a andnegative transistor 312 a may receive or be coupled with the positivein-phase local oscillator input signal 202 a. In one embodiment, thesources of both the positive transistor 310 a and negative transistor312 a may be coupled with each other and the cascode circuit 406. In oneembodiment, the drain of the positive transistor 310 a may provide apositive output signal 206 a, and the drain of the negative transistor312 a providing a negative output signal 206 a. It is understood thatthe configuration of the negative in-phase sub-portion 408 b and thequadrature-phase portion may be analogous to the positive in-phasesub-portion 408 a, described above.

In one embodiment, the cascode circuit 406 may include a top part and abottom part. Although once again, it is understood that the terms “top”and “bottom” are relative terms used to differentiate the elements ofthe cascode circuit 406 and in no way limit or dictate the physicalorientation of the disclosed subject matter. In one embodiment, the topof the cascode circuit 406 may include a biasing transistor 314 aconfigured to receive a biasing input signal 302. In one embodiment, thegate of the biasing transistor 314 a may be coupled with the biasinginput signal 302. In one embodiment, drain of the biasing transistor 314a may be coupled with the local oscillator switching circuit 304. In oneembodiment, source of the biasing transistor 314 a may be coupled withthe bottom of the cascode circuit 406. It is understood that theconfiguration of the negative in-phase sub-portion 408 b and thequadrature-phase portion may be analogous to the positive in-phasesub-portion 408 a, described above. In one embodiment, the top of thecascode circuit 406 of the switchable partial step mixer unit cell 210may be substantially equivalent to the top of the cascode circuit 406 ofthe switchable full step mixer unit cell 208. In one embodiment, thefirst part 305 of the switchable partial step mixer unit cell 210 may besubstantially equivalent to the first part 305 of the switchable fullstep mixer unit cell 208.

In one embodiment, bottom of the cascode circuit 406 may be configuredto receive both a positive baseband input signal 204 a and a negativebaseband input signal 204 b. In one embodiment, the second part 407 ofeach sub-portion of the switchable partial step mixer unit cell 208 mayinclude the bottom of the cascode circuit 406. In one embodiment, thebottom of the cascode circuit 406 may include a positive partial stepbaseband transistor 414 a and a negative partial step basebandtransistor 416 a.

In one embodiment, the gate of the positive partial step basebandtransistor 414 a may receive or be coupled with the positive in-phasebaseband signal 204 a. In one embodiment, the gate of the negativepartial step baseband transistor 416 a may receive or be coupled withthe positive in-phase baseband signal 204 b. In one embodiment, thedrain of the partial step baseband transistors 414 a & 416 a may becoupled with the top of the cascode circuit 406. In one embodiment, thesource of the partial step baseband transistors 414 a & 416 a may bethought to be coupled with a ground, relative or absolute.

In one embodiment, the partial step baseband transistors 414 a & 416 amay each include a width, aW and bW respectively. In one embodiment, thewidths may affect the effective resistance of the transistors. In oneembodiment, these widths may affect the gain provided by the positivein-phase sub-portion 408 a and may affect the amount of current allowedto flow through the partial step baseband transistors 414 a & 416 a. Inone embodiment, the widths, aW and bW, of the partial step basebandtransistors 414 a & 416 a may affect the voltage at the interfacebetween the top and bottom of the cascode circuit 406.

In one embodiment, the widths, aW and bW, of the partial step basebandtransistors 414 a & 416 a may be configured such that the sum of thewidths is substantially equal to the width, W, of the full step basebandtransistor 316 a of FIG. 3 (e.g., 1=a+b). In such an embodiment, thevoltage at the interface between the top and bottom of the cascodecircuit 406 may be kept, during operation, substantially equal to thevoltage at the interface between the top and bottom of the cascodecircuit 306. In one embodiment, these voltages, or the substantiallyequivalent portions thereof, may be direct-current (DC) voltages. In oneembodiment, the DC current through the cascode switch 406 and the localoscillator switching circuit 304 of the switchable partial step mixerunit cell 210 may be substantially equal to their corresponding elementsof the switchable full step mixer unit cell 208. But, in one embodiment,the signal currents resulting from the switchable partial step mixerunit cell 210 may be scaled down compared to the signal currents of theswitchable full step mixer unit cell 208. In one embodiment, the gainprovided due, at least in part, to the second part 407 may be equal toan inverse power of 2 (e.g., a−b=½^(n), where n=1, 2, 3, etc.).

In one embodiment, the negative sub-portions of the switchable partialmixer unit cell 210 (e.g., in-phase negative sub-portion 408 b) may flipthe relative widths of the partial step baseband transistors 414 b & 416b, as compared to their positive counter-parts. For example, if in thepositive sub-portion 408 a the baseband transistor 414 a has a width ofaW and the baseband transistor 416 a has a width of bW, then, in oneembodiment, in the negative sub-portion 408 b the baseband transistor414 b may have a width of bW and the baseband transistor 416 b may havea width of aW. In one embodiment, this may allow the weighing of thegain of the positive and negative portions baseband signal 204 to occurin the respective sub-portions of the switchable partial mixer unit cell210. In one embodiment, with such a structure, the gain step whenswitching from partial mixer unit cell to a full mixer unit cell mayremain constant over temperature.

FIG. 5 is a flowchart of a technique 500 for controlling the gain of anelectrical signal in accordance with the disclosed subject matter. Block502 illustrates that, in one embodiment, a request to amplify anelectrical signal may be received. In one embodiment, the electricalsignal may be utilized as part of a Wideband Code Division MultipleAccess (WCDMA) protocol. In one embodiment, the mixer unit 110 of FIG. 1may receive this request, as described above.

Block 504 illustrates that, in one embodiment, a switchable partial stepmixer unit cell may be activated or turned on in order to amplify theelectrical signal by a predetermined step increment, wherein thepredetermined step increment is less that that of a full step. In oneembodiment, the predetermined step increment may be referred to as apartial gain step. In one embodiment, the mixer unit 110 of FIG. 1 mayturn on the switchable partial step mixer unit cell 210 of FIG. 2, asdescribed above.

Block 506 illustrates that, in one embodiment, an additional request toamplify an electrical signal may be received. In one embodiment, themixer unit 110 of FIG. 1 may receive this request, as described above.

Block 508 illustrates that, in one embodiment, a determination may bemade as to whether or not the requested additional amplification willresult in a total gain reachable using full gain steps. In oneembodiment, a plurality of partial gain steps may be substantiallyequivalent to a, or an integer number of, full gain steps, as describedabove. In one embodiment, the mixer unit 110 of FIG. 1 may make thisdetermination, as described above.

Block 510 illustrates that, in one embodiment, if the additional gainwill not result in a total gain reachable using full gain steps, anadditional switchable partial step mixer unit cell may be activated orturned on. In one embodiment, the mixer unit 110 of FIG. 1 may turn onthe switchable partial step mixer unit cell 210 of FIG. 2 or equivalentelement, as described above.

Block 512 illustrates that, in one embodiment, if the additional gainwill result in a total gain reachable using full gain steps, the activeswitchable partial step mixer unit cell(s) may be deactivated or turnedoff, and a switchable full step mixer unit cell. In one embodiment, themixer unit 110 of FIG. 1 may turn off the switchable partial step mixerunit cell 210 of FIG. 2 and turn on the switchable full step mixer unitcell 208 of FIG. 2, as described above.

In one embodiment, the technique 500 may include the ability to decreasethe amount of amplification. In such an embodiment, the Blocks analogousbut opposite in result to Blocks 506, 508, 510, & 512 may be included.In one embodiment, the technique 500 may include the ability to adjustthe gain, positive or negative, applied to a signal in a non-continuousfashion. In such an embodiment, a number of switchable full gain stepmixer unit cells and a number of switchable partial gain step mixer unitcells may be activated substantially simultaneously, allowing theintermediate gain values to be skipped.

Implementations of the various techniques described herein may beimplemented in digital electronic circuitry, or in computer hardware,firmware, software, or in combinations of them. Implementations mayimplemented as a computer program product, i.e., a computer programtangibly embodied in an information carrier, e.g., in a machine-readablestorage device or in a propagated signal, for execution by, or tocontrol the operation of, data processing apparatus, e.g., aprogrammable processor, a computer, or multiple computers. A computerprogram, such as the computer program(s) described above, can be writtenin any form of programming language, including compiled or interpretedlanguages, and can be deployed in any form, including as a stand-aloneprogram or as a module, component, subroutine, or other unit suitablefor use in a computing environment. A computer program can be deployedto be executed on one computer or on multiple computers at one site ordistributed across multiple sites and interconnected by a communicationnetwork.

Method steps may be performed by one or more programmable processorsexecuting a computer program to perform functions by operating on inputdata and generating output. Method steps also may be performed by, andan apparatus may be implemented as, special purpose logic circuitry,e.g., an FPGA (field programmable gate array) or an ASIC(application-specific integrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read-only memory ora random access memory or both. Elements of a computer may include atleast one processor for executing instructions and one or more memorydevices for storing instructions and data. Generally, a computer alsomay include, or be operatively coupled to receive data from or transferdata to, or both, one or more mass storage devices for storing data,e.g., magnetic, magneto-optical disks, or optical disks. Informationcarriers suitable for embodying computer program instructions and datainclude all forms of non-volatile memory, including by way of examplesemiconductor memory devices, e.g., EPROM, EEPROM, and flash memorydevices; magnetic disks, e.g., internal hard disks or removable disks;magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor andthe memory may be supplemented by, or incorporated in special purposelogic circuitry.

To provide for interaction with a user, implementations may beimplemented on a computer having a display device, e.g., a cathode raytube (CRT) or liquid crystal display (LCD) monitor, for displayinginformation to the user and a keyboard and a pointing device, e.g., amouse or a trackball, by which the user can provide input to thecomputer. Other kinds of devices can be used to provide for interactionwith a user as well; for example, feedback provided to the user can beany form of sensory feedback, e.g., visual feedback, auditory feedback,or tactile feedback; and input from the user can be received in anyform, including acoustic, speech, or tactile input.

Implementations may be implemented in a computing system that includes aback-end component, e.g., as a data server, or that includes amiddleware component, e.g., an application server, or that includes afront-end component, e.g., a client computer having a graphical userinterface or a Web browser through which a user can interact with animplementation, or any combination of such back-end, middleware, orfront-end components. Components may be interconnected by any form ormedium of digital data communication, e.g., a communication network.Examples of communication networks include a local area network (LAN)and a wide area network (WAN), e.g., the Internet.

While certain features of the described implementations have beenillustrated as described herein, many modifications, substitutions,changes and equivalents will now occur to those skilled in the art. Itis, therefore, to be understood that the appended claims are intended tocover all such modifications and changes as fall within the scope of theembodiments.

What is claimed is:
 1. An apparatus comprising: at least one switchablefull step mixer unit cell, wherein the switchable full step mixer unitcell is configured to, when the full step mixer unit cell is turned on,adjust the gain experienced by at least one electronic signal by a fullstep increment; and at least one switchable partial step mixer unit cellconfigured to, when the partial step mixer unit is switched on, adjustthe gain experienced by the electronic signal by a predetermined stepincrement less than that of a full step increment.
 2. The apparatus ofclaim 1 wherein each of the switchable full step mixer unit cellsincludes a mixer circuit; wherein each of the at least one switchablepartial step mixer unit cells includes a mixer circuit; and wherein eachof the mixer circuit includes at least two sub-portions.
 3. Theapparatus of claim 2 wherein each sub-portion of each mixer circuitincludes: a first part having a local oscillator switching circuit and atop of a cascode circuit, and a second part having a bottom of a cascodecircuit.
 4. The apparatus of claim 3 wherein the first part of the mixercircuits of each of the switchable full step mixer unit cells and the atleast one switchable partial step mixer unit cells are substantiallyidentical.
 5. The apparatus of claim 3 wherein the local oscillatorswitching circuit is configured to receive a local oscillator inputsignal, and the top of the cascode circuit is configured to receive abiasing input signal.
 6. The apparatus of claim 5 wherein the localoscillator switching circuit includes a positive transistor and anegative transistor, each transistor having a gate, a source, and adrain; and wherein: the gate of each transistor is coupled with thelocal oscillator input signal, the sources of the transistors are bothcoupled with each other and the cascode circuit, the drain of thepositive transistor is configured to provide a positive output signal,and the drain of the negative transistor is configured to provide anegative output signal.
 7. The apparatus of claim 3 wherein the secondpart of each sub-portion of each of the switchable full step mixer unitcells is configured to receive a baseband input signal; and wherein thesecond part of the positive sub-portions is configured to receive apositive baseband input signal, and the second part of the negativesub-portions is configured to receive a negative baseband input signal.8. The apparatus of claim 7 wherein the second part of each sub-portionof each of the at least one switchable partial step mixer unit cells isconfigured to receive both a positive baseband input signal and anegative baseband input signal.
 9. The apparatus of claim 8 wherein thesecond part of each sub-portion of each of the switchable full stepmixer unit cells includes a full step baseband transistor, having agate, a drain and a width; and wherein: the gate of the full stepbaseband transistor is coupled with the baseband input signal, and thedrain is coupled with the top of the cascode circuit.
 10. The apparatusof claim 9 wherein the second part of each sub-portion of each of the atleast one switchable partial step mixer unit cells includes a positivepartial step baseband transistor having a gate, a drain and a width,wherein: the gate of the positive partial step baseband transistor iscoupled with a positive baseband input signal, and the drain of thepositive partial step baseband transistor is coupled with the top of thecascode circuit, and a negative partial step baseband transistor havinga gate, a drain and a width, wherein: the gate of the negative partialstep baseband transistor is coupled with a negative baseband inputsignal, and the drain of the negative partial step baseband transistoris coupled with the top of the cascode circuit.
 11. The apparatus ofclaim 10 wherein the sum of the widths of the positive partial stepbaseband transistor and the negative partial step baseband transistor issubstantially equal to the width of the full step baseband transistor.12. A system comprising: a baseband filter configured to producebaseband signals; and a mixer unit configured to produce an outputsignal based upon the baseband signals; and the mixer unit comprising:at least one full step mixer unit cell, wherein the full step mixer unitcell is configured to adjust the gain experienced by the basebandsignals by a full step increment, at least one partial step mixer unitcell configured to adjust the gain experienced by the baseband signalsby a predetermined step increment less than that of a full stepincrement.
 13. The system of claim 12 wherein the mixer unit includes atleast 2¹⁰ full step mixer unit cells.
 14. The system of claim 12 thesystem further including the amplifier and an antenna configured totransmit the output signal.
 15. The system of claim 12 wherein thebaseband filter is configured to utilize a Wideband Code DivisionMultiple Access (WCDMA) protocol.
 16. The system of claim 12 wherein themixer unit provides a maximum gain of between 60 dB and 72 dB,inclusive.
 17. The system of claim 16 wherein the full step incrementgain of each of the full step mixer unit cells is substantially between5 dB and 8 dB, inclusive; and the partial step increment gain of each ofthe partial step mixer unit cells is substantially between one-eighthand one-half, inclusive, of the full step increment gain.
 18. A methodcomprising: requesting amplification of an electrical signal; turning ona partial step mixer unit cell to amplify the electrical signal by apartial predetermined step increment less than that of a full step;requesting additional amplification of the electrical signal; turning onone or more additional partial step mixer unit cells to amplify theelectrical signal, until the full gain step has been reached; once thesum of the partial steps is equal to the full step, turning off thepartial step mixer unit cells and turning on a full step mixer unitcell.
 19. The method of claim 18 wherein turning on a partial step mixerunit cell includes multiplying a baseband filtered signal with a localoscillator signal.
 20. The method of claim 19 wherein turning on apartial step mixer unit cell includes utilizing a circuit including: alocal oscillator switching circuit and a cascode circuit, the cascodecircuit having a top half coupled between the local oscillator switchingcircuit and the bottom half of the cascode circuit, wherein the bottomhalf of the cascode circuit includes two bottom transistors configuredin parallel; wherein the sum of the widths of the two bottom transistorsof the cascade circuit is substantially equal of the width of a bottomcascode transistor included as part of the full step mixer unit cell.